Charge air cooler, also referred to in the transportation industry as intercooler, is an important component of the internal combustion engine cooling system. The role of the CAC is to reduce the engine inlet temperature, increase the intake density, improve fuel utilization, and reduce emissions of toxic and harmful gases. If the charge air cooler has poor cooling performance or leakage, the service life of the internal combustion engine will be directly affected, even to the point that an expanding cylinder may fail. The structure of a main header is an important component of a core body of the charge air cooler, and its brazing strength with tubes directly affect the sealing performance and reliability. Therefore, the design of the main header is profoundly important.